I first heard this very short classical riff when I was only 18. Ritchie Blackmore just blew me away at how perfectly he had played it. I had forgotten for years and years what album it was on and heard it again by utter chance on the Made In Japan album, remastered version. It's at 55:30 and is the last little ten second riff just before he starts the long lead-in to Space Truckin'. I think it may be a piece by Bach, but I just don't know the name of it. If anyone knows the answer to this mystery, I'd be very grateful to know the answer! Thanks very much!